Contact heat evoked potentials and habituation measured interictally in migraineurs

Background: A lack of habituation of different evoked potential modalities in migraine patients in-between attacks has been suggested. Methods: This study investigates cortical response after painful stimuli evaluated by contact heat evoked potentials (CHEPs) and quantitative sensory testing (QST) during the migraine-free interval. We enrolled 22 migraine patients and 22 healthy subjects. Results: Cortical potentials after contact heat stimulation of the cheeks and the volar forearm at a temperature of 51 degrees C showed significantly reduced A-delta-amplitudes in patients and healthy controls. When the subjects' attention was drawn to an arithmetic task, a partial lack of habituation of amplitude could be seen in migraine patients. QST did not show any difference between migraineurs and controls. Conclusion: Our findings can be primarily deemed to demonstrate that patients and healthy controls show significantly lower amplitudes while performing the calculation task. Without performing the calculation task we could not show the expected lack of habituation in migraineurs. Yet, while performing the calculation task our results partly suggest that hypothesis.